Sulfonate detergent compositions



, ,W 2,944,028, SULFONATE DETERGENT coMrosmoNs j Richard D.staynenberkeley, Calif.,"assignor to California Re'searchjCorporation,jfia'n Francisco, Calif, a

. corporationoflDelaware This invention relates to improved washingformulations 1 weakv and lacy and rapidly collapse and disappear duringthe agitation of the contents of the tub containing the washing solutionand the soiled articles. This constitutes a serious drawback since aconsiderable proportion of the consumer publicstill believe that a largevolume of suds ;is concomitant with the washing efliciency and gives anrndicatlon of the amount of the detergent necessary for 3 effectivewashing.

.zTfliS deficiency with respect to theability of producing V persistentsuds is noted only in using solutions of poly- @propylcne benzenesulfonates derived from propylene which containa branched-chainpolypropylene benzene 1 sulfonate as their active detergentfcomponent,and which arecapableof producing a large. volume of stable sudsmaintaining a satisfactory highslevel in the continuously agitatedaqueous solutions thereof in the presence of soil. C -C polypropylenebenzene sulfonates, which may be also designated as sulfonatedmonophenyl-substituted acyclic C -C polypropylenes are known in the artto beeffective detergents and, when suitably formulated, are

used in a variety of industrial and household cleaning applications,particularlyin the washing of soiled clothes, fabrics and dishes.A-number of'washing formulations, based on these polypropylenebenzenesulfonate detergents and containing different additives for the,purpose of modifying one or another particular property of thesedetergents, have been described in the art. In U.S. Patent 2,712,530,Baumgartner proposed to add to these detergent sulfonates from 5 to 50%by weight of a secondary alkylary-l sulfonate ofthe general structuralformula in which R was a straight-chain Ci-C alkylgroup, R"

was a straight-chain Cg-C14 alkyl group, the sum of R and R" equalled 9to 15 carbons and M was an alkali metal. The addition of this secondaryalkyl benzene sulfonate was said' to improve the detergent property ofthe polypropylene benzene sulfonate at concentrations below about 0.25%

British Patent No. 702,013 disclosed the addition to C -C polypropylenebenzene sulfonate detergents of at least by weight of sulfonated2-phenyl alkanes containing a straight alkyl chain of 10 to 16 carbonatoms in their alkane portion for the purpose of reducing the cakingtendency of the formulations containingthe aforementioned detergentpolypropylene benzene sulfonates as their main active component.

. In his U.S. Patent 2,477,383, Lewis described detergent branched-chainpolypropylenebenzene sulfonates (sulfonated mono-phenyl substitutedacyclic polypropylenes), pointingout that commercial: polypropylenebenzene snlfonates characterized by an average contento'f about 12barbonatorns in the polypropylene chaiiiwere particularly effective asdetergent ingredients in formulations employed for a great manyhouseholdand industrial applications. It'has been noted in the. actual practicethat dilute soft water solutions of these commercialC '(dodecyl)polypropylene benzene sulfonate detergents, when employed. in the tub ofagitator-type washing machines at low-use concentrationstof the order of0.15%) and attemperatures above 100 F., and usually from about 120 toabout 1410" F.,- generally fail to produce an adequate volume ofpersistent suds, lasting the entire periodbfagitation and, particularly,in contact with soil (soiled clothes, etc.) Although the volume of sudsinitially produced on starting the washing cycle is relatively large,these suds are tetramer fractions, such as commercial dodecyl benzenesulfonate It is clearlyin contrast with thefoam perforrm ance ofpolyprop ylen'e' benzene sulfonates derived from propylene pentamerfractions characterized by an aver-Q age content of about 15 carbonatoms, the solutions of which produce adequate and persistent suds, andwhich therefore need not be improved as regards their foam per-.

formance.

A number of additives and of combinations of additives 5,; have beenproposed in the past for the purpose of im-, proving thefoam'performance of commercial C poly- I propylene benzene sulfonateslHowever, in most cases, these additives failto secure, in warm softwater solutions ofthe1 polypropylene benzene sulfonatefietergents a sat-1 isfactory'foar'n which would persist under' continued agitation in thepresence of soil. The term soft water, as em ployed in this description'designateswater of a Ca-Mg hardnessfrom about 50 to less than aboutppm, calculated as parts per million of CaCO and MgCO in 3 a, weightratio of about 2:1. Furtherm0re, most of the proposed additives werecomparatively expensive and their employment resulted in an undueincrease of the sales price of the final detergent formulations.

It is therefore the object of the present invention to provide a new andinexpensive foam-improving agent for commercial C polypropylene benzenesulfonates, capa ble of assuring persistence of the suds formed bydilute washing solutions of these detergent sulfonates under agitationand in the presence of soil.

I found that the persistence of the suds produced by dilute solutions ofcommercial C polypropylene benzene I sulfonates can be markedly andunexpectedly enhanced. by combining these detergent sulfonates witheffective proportions of an improving agent from the group ofstraightchain alkyl benzene sulfonates characterized by the gen eralformula V SOaM inwhich n is an integer from 5 to 7, n is an integer from5 to 8, and M is selected from thegroup consisting of? alkalimetal andammonium cations. As examples of. these straight-chain alkylbenzenesulfonates, there may: be mentioned: 7-phenyl tetradecane sulfonate,8.-phenyit hexadecane sulfonate, 9-phenyl"octade'cane sulfonate and: thelike. When a sulfonate having a structure correspond, ing to thisformula is added to-a' commercial C poly-g propylene benzene sulfonatedetergent, dilute aqueous solutions of the resulting combination inconventional low-. use concentrations from about 0.1 .upto about 0.2%form: large volumes of suds, and these suds'persist above the surface ofthe solution in'the tube of a washing machine; notwithstanding thecontinued agitation of the contents of; the tub and notwithstanding thepresence therein of soiled I clothes or fabrics.

Patented July 5, 1960 based on the total weight of sulf'ona-tes inthedetergent composition.

This improvement in the foam persistence of commercial C polypropylenebenzene sulfonate detergents is entirely unexpected and specific to thegroupof alkylbenzene sulfonate additives described hereinbefore. The

length. of the alkyl chain and the point of attachment to the aromatic(benzene) ring in the molecule of the sulfa-- nat'e additive arecritical tothe production of an adequate and persistent layer of sudsabove the liquid surface in the tub. This specificity is surprisingbecause'nei-ther the sulfonate detergency improvers of' theaforementioned Bau'mgartner patent, such as 6-phenyl dodecane sulfonate,nor the sulfonat'ed- Z-phenyl alkane caking preventives'of BritishPatent 702,018, for instance, Z-phenyl dodecane andtetradecanesulfonates, are capable of providing the desired persistent suds abovethe liquid level in the tub of an agitator-type washing machine.

The presence of the foam-improving additive of the invention does notdetract in any way from the excellent soil-removing ability (detergency)of the C polypropylene benzene sulfonates.

The polypropylene benzene sulfonate detergents which have an averageoftwelve carbon atoms in the polypropylene chains and the foam persistenceof which is enhanced by their combination with-the aforementionedsulfonate additive, are generally employed in the form of water-solublealkali metal and ammonium salts, sodium salts being preferred.Heavy-duty formulations based on these C polypropylene benzenesulfonates usually contain from about 20 to. about 35% of the,sulfonates by weight of the. total solids. in the formulation.

Formulations containing these detergent commercial C polypropylenebenzene sulfonates in combination with from 5. to 50% by weight ofthesulfonate additive for achieving foam persistence may containconventional Water-soluble inorganic salt detergent builders, such as.salts of stronginorganic acids, exemplified by sodium sulfate, sodiumchloride and potassium. chloride, ammonium; sulfate and/or alkalinesalts of weak inorganic acids, exemplified by various polyphosphates,for instance,

tetrasodium pyrophosphate, sodium tripolyphosphate, so-

dium hexametaphosphate, and salts, such as sodium carbonate, sodiumsilicate. and borax. From. 60 to 90 parts by weight ofthese inorganicsalt detergent builders, prefer-' ably as sodium salts, may be presentin each 100- parts by weight of a detergent formulation containing thetwo aforementioned sulfonates (detergent and additive) in accordancewith the invention. Where heavy-duty formulations are prepared, fromabout 10 to about 90% by weight of the inorganic salt. builders mayconsist of inorganic polyphosphates, such as Na P O and Na P O and thelike. Fatty acid alkylolamides such as lauric isopropanolamide andlauric ethanolarnide known in the art to enhance the tolerance of thefoam with respect to soil, may also be included in the detergentformulations of this invention inconventional small quantities. Other.conventional additives, such as carboxymethylcellulose and oxidizedcellulose (celluronic acid) organic builders or extenders, anti-cakingagents, optical bleaches, cor1'o sion inhibitors, perfume, dyes and skinemollients, such asalkyl glycines, may be employed in the sulfonatedetergent formulations. of the. present invention, the total weight ofthese various additives seldom exceeding 5% by weight of the entireamount of solids in a formulation, and, in all events, being such thatthe presence of these additives does not interfere with the improvedpersistence,

of the suds produced by the. agitated dilute solutions of,

the detergent formulations.

The preparation of the detergent formulations of this invention may beeffected by blending the detergent C polypropylene benzene sulfonateswith the sulfonate additive for the improvement of foamv persistenceintoan,

aqueous slurry, or solution, adding the desired builders and otheradditives to the slurry, and reducing this slurry by drying, ifnecessary, to the desired form (liquid concentrate, paste or solidparticle).

Another way of preparing, the, detergent formulations of the presentinvention consists in blending the C polypropylene benzeneswith. fromabout.- 5. to, about 50%} by weight thereof, of suitable. mono-phenyl.substituted.

straight-chain. alkanes and then. sulfonating the, resulting hydrocarbonblend with the aid. of an appropriate sulfjonating agent, such as fumingsulfuric acid, neutralizing the sulfonation product mixture, introducinginto the resulting neutralized; slurry the desiredbuilders and otheradditives and, finally, reducing the slurry to the desired form, such asliquid concentrate, paste or solid particle.

The improvement in the foam persistence was re peatedly observedby'preparing dilute aqueous, solutions of different detergentformulations containing in their or ganic active portion a blend of- Cpolypropylene benzene sulfonates and of from 5 to 50% by weight. ofstraight chain alkylbenzene sulfonates of the previously given formula Vand testing; these solutions in an agitator-type automatic washingmachine under the conditions approximating thoseof actual householdlaundering practice. The results of the tests werecompared with theresults of numerous test runs which employed detergent formulationscontain:

. .ing blends of the C polypropylene benzene sulfonate detergents withstraight-chain alkylbenzene sulfonates other than those defined by theaforegiven formula, and also with the results of test runs in which nosulfonate additive was blended with the polypropylene benzene sulfonatedetergent component. The solutions for the tests were prepared by usingwater of 50 ppm. hardness, the

hardness being figured as parts per million of CaCO and MgCO hardness ina weight ratio of 2:1.

The tub of the machine was filled with water, and

a specified quantity of soil thoroughly distributed therein,

followed by such a quantity of. the detergent formulation as to give a0.15% concentration in the water. Thereafter, a charge of clean cottontowels was placed in the tub assuring aneven distribution below thesurface of .the solution which had a temperature of about F. Theagitation was, commenced and the level of the suds .was added to thewash solution, and the run resumed for 5' minutes more to complete the20 minute cycle.

'Persistence of the suds was rated as follows: When suds lasted througha complete washing cycle of 20 minutes, or even longer, and presented asubstantially unbroken blanket of foam of /2 or more above the surfaceof the liquid in the tub, their persistence was rated to be Good. Whensuds lasted through the whole washing cycle but rose to less than /2"above, the liquid surface and did not. cover the entire surface of thewashing solution, the persistence was rated to be Fair." Finally, whenpractically no suds were formed or, if formed, the suds disappearedbefore the completion of they washing cycle, the persistence was ratedto be Poor.

In an illustrative test series, a representative formulation contained20 parts of sodium polypropylene benzene sulfonate. having an average of12 carbon atoms in the polypropylene chain, B'Oparts .of sodiumtripolyphosphate,

stance 3 parts by weight of the polypropylene benzene sulfonatedetergent by the sulfonate additive, and used in the tests as describedhereinbefore.

Representative data from this test series are tabulated on the followingpage.

and data are merely illustrative of the present invention, and that itmay be modified without substantial departure from the spirit and scopethereof, provided that the modifications fall within the scope of thefollowing claims:

-I claim: V V

1. A detergent composition consisting essentially of a. water-solublepolypropylene benzene sulfonate detergent having an average carboncontent in the polypropylene V 10 chain of about 12 carbon atoms, and,in an amount suf- Suds persistence evaluation data Commercial CuPolypropyl- Parts By Suds Per- Test Run No. one Benzene SultanateDesulfonate Additive Weight sistence tergent in Parts By Weight Addl-Rating tive 1 20 None Poor. 2 2a do r. Do. 3 17 l-phenyl tetradecanesulfonate- 3 Do. 4 30 l-phenyl octadecane sulfonate.-. 3 Do. 1 5 172-pheny1 hexadecane sulfonate 3 Fair.

6 17 6 phenyl dodecane sulfonate- 3 Poor. 7 17 ll-phenyl doeosanesulfonate- 3 Do.

a 9n Q-phenyl octadecane sulfonate"--- 1 Fair. 9 17 do 3 Good. 10 17S-phenyl hexadecane su1fonate. 3 Do. 11 17 7-phenyl tetradecanesulfonatm 3 Do. 12 7-phenyl tetradecane sulfonate. 10 Do. 13 G15(pentamer) polypropylene None"; Do.

benzene sulfonate 20. r

The data shown in the table clearly indicate the remarkable improvementin the foam persistence of dilutev aqueous solutions of the formulationscontaining C polypropylene benzene sulfonate detergents, under theconditions of agitation and in the presence of soil, due to theintroduction of straight-chain alkylbenzene sulfonate additives inaccordance with the invention (runs 8, 9, 10, 11 and 12).- The tablefurthermore shows that straightchain alkylbenzene sulfonates other thanthose of the subject invention are ineffective for the purpose ofproviding good foam persistence (runs3, 4, 5, 6 and 7),.when present inthe solutions of washing formulations which contain C polypropylenebenzene sulfonate detergents. Run 13 is given to emphasize thedeficiency of the tetramer polypropylene derived detergents (runs 1 and2) in regard to the foam persistence as contrasted with the fpentamerpolypropylene derived detergents.

Throughout the aforegiven description of my invention the termcommercial C polypropylene benzene sulfonate detergent refers to thosepolypropylenebenzene sulfonate detergent materials which have beenobtained from a tetramer fraction of polypropylene characterized by anaverage content of about 12 carbon atoms.

It is to be understood that the aforegiven description ficient toenhance the sudsing properties of said polypropylene benzene sulfonate,of a straight-chain alkylbenzene sulfonate having the formula CH8-(CHg)n(oH.).. cHt wherein n is an integer from 5 to 7, n is an integer from 5to 8, and M is a radical selected from the group consisting of alkalimetals and ammonium.

2. A built detergent composition consisting essentially of 10 to 40parts, by weight, of the composition of claim 1 and to parts, by weight,of inorganic salt detergent builders.

1. A DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF A WATER-SOLUBLEPOLYPROPYLENE BENZENE SULFONATE DETERGENT HAVING AN AVERAGE CARBONCONTENT IN THE POLYPROPYLENE CHAIN OF ABOUT 12 CARBON ATOMS, AND, IN ANAMOUNT SUFFICIENT TO ENHANCE THE SUDSING PROPERTIES OF SAIDPOLYPROPYLENE BENZENE SULFONATE, OF A STRAIGHT-CHAIN ALKYLBENZENESULFONATE HAVING THE FORMULA